This may not be exactly what you're going for, but it could be helpful in gathering data and encouraging people to follow through with it. If you were to make a

This may not be exactly what you're going for, but it could be helpful in gathering data and encouraging people to follow through with it. If you were to make a book related "outside your comfort zone" website, what you could do is get recommendations from authors. So for example, if I happen to like Stephen King, show me a list of books that Stephen King likes to read, but that are completely different from the kind of books that he writes. It might be a bit tricky to build up the database at first, especially considering authors might be a bit hesitant to recommend their competition, but I think it would be a really cool idea.